_base.headings.scss

This module defines the font-sizes for your headings. It provides variables for you to override:

$inuit-heading-size-1:  36px !default;
$inuit-heading-size-2:  30px !default;
$inuit-heading-size-3:  24px !default;
$inuit-heading-size-4:  20px !default;
$inuit-heading-size-5:  16px !default;
$inuit-heading-size-6:  14px !default;

Alter these variables to your likes.